Octopus tariffs - a quick comparison

Tim441 · 2025-08-31T10:38:04Z

I've drawn up a comparison list for friends & family. Please suggest corrections/additions. I know its possible to go on and on with so many variables! So just focused on initial guide. Octopus Energy Tariffs – Quick Guide Flexible (Standard) Variable rates with the Ofgem cap. Typically the most expensive. Most people can save with an alternative tariff. Fixed Rates fixed for 12 months. Typically ~15% cheaper than Flexible. A safe, predictable option — unless wholesale prices fall during the contract. Tracker Daily rate linked to wholesale prices. Long-running tariff, typically 20–30% cheaper than Flexible. Occasionally higher on cold/low-wind days, but capped and usually cheaper over the year. Agile Half-hourly wholesale-linked pricing. Best for homes with batteries or ability to time-shift use. Can go very low (even negative), but also spike at peak times. With smart shifting/batteries, savings of 50%+ possible. Rates are capped by Octopus. Go Like Economy 7: very cheap overnight (4 hours), higher daytime rates. Ideal for EVs, storage heaters, heat pumps + batteries. Intelligent Go Smarter version of Go with ~6 hours overnight at ~7p/kWh. Requires a compatible EV/charger. Great with batteries and/or time-shifting. Potential savings up to 75% vs Flexible if optimised. Flux For homes with solar + batteries. Cheap overnight import, premium export rates in the evening. Needs manual scheduling or automation for best results. Intelligent Flux Same as Flux but fully automated for GivEnergy battery users. Cosy For heat pump households. 3 cheap periods daily to align heating. Best with a battery. Around 20% cheaper than Flexible. Power Pack For V2G (vehicle-to-grid) setups. Lets you charge your EV for free by exporting back to the grid. Still early-stage; requires V2G-compatible EV + charger.

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Majordennisbloodnok

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08/10/2025 3:44 pm

Does indeed need checking, @tim441.

Neither Homely nor Havenwise currently support the Grant that @nickmorgan has specified (Homely does do Grant, but not that model).
ChatGPT is suggesting Home Assistant should "co-ordinate" with Homely/Havenwise, but neither of them offer that functionality.
There does seem to be an Andersen integration for Home Assistant but it's a community-created one and looks to me like it has rather limited functionality and in particular doesn't seem to offer the ability to tell the charger to start charging. Crucially, however, it does at least have the ability - at least apparently - to get the charger's status, meaning the home battery could at least be told to change its minimum charge level to 90% or above so the car can never be significantly charged from the home battery.
The efficiency gains from Homely/Havenwise vs a well-configured and installed heat pump already set up with weather compensation are far lower than the marketing blurb might suggest. If Havenwise ever do start supporting Grant, even those marginal improvements might be worth the modest fee but Homely is a different story. The only way I've seen so far for Home Assistant to connect to a Grant heat pump is via an integration that uses modbus and Homely's local box of tricks uses the same modbus connection that would be needed.
The ChatGPT report purely looks at the technically preferred solutions and seems to be recommending Home Assistant as the central point. For me, that's a good solid recommendation but then I work in IT. This would not be a good suggestion if @nickmorgan is reticent about setting up a Home Assistant instance; it's not hard but does require a bit of a learning curve which not everyone is comfortable with.
If we assume (big if, I know, but we have to start somewhere) that the Grant is set up correctly and is running well under weather compensation, the ChatGPT report ignores the option of simply letting it continue like that, adopting Octopus Go as the tariff and then using the charger app and the Fox app to schedule EV charging and home battery charging during the cheap periods. It's not the optimal solution but it's perhaps 80-90% there for almost no effort.

If @nickmorgan is up for having a go with Home Assistant, that's well worth a try, especially since that then provides a platform for other non renewables related stuff like integrating smart switches, CCTV, home entertainment, robot vacuum cleaners and so on. If not, I'd go with my last bullet point above and keep it really simple.

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Batpred

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10/10/2025 4:59 pm

Great summary, @majordennisbloodnok!

I'd take the home assistant route. Very low investment and the possibilities are endless.

I cannot comment on whether the Grant heat pump will become popular, but if so, chances are the integration will get better. I just had to switch my car integration to a completely new one as the manufacturer end of lifed the previous API and it took me a few minutes to adjust the dashboards.

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